The present invention relates to a retractable helicopter landing gear.
Helicopters are known to comprise a front landing gear, and two rear landing gears fixed to either side of the fuselage. Each has a wheel, and serves to cushion the downward energy of the helicopter when landing.
Landing gears may be fixed or retractable. In flight, retractable landing gears are set to a stowed or withdrawn position, in which the wheels are housed inside housings to reduce drag and fuel consumption of the helicopter, and are moved by hydraulic actuators between the stowed position and a lowered or deployed position for landing or takeoff.
When landing on “soft” ground, such as snow or sand, the wheels must be prevented from sinking into the ground, so as to maintain the attitude of the helicopter when landing, and ensure stable support on the ground and easy takeoff. The same substantially also applies when landing on uneven ground.
This is normally done by attempting to discharge the weight and downward force of the helicopter to the ground over a wider supporting area than that provided by one-wheel landing gears. One known solution is to employ landing gears with two relatively large-diameter wheels, but has the drawback of the additional wheel per landing gear greatly increasing the weight of the helicopter.
As opposed to dual wheels, another known solution is to replace the rear landing gear wheels with skids fixed by steel cables. The relatively large underside surface area of known skids, however, prevents withdrawal of the landing gears, with the result that the skids increase drag and, therefore, fuel consumption, especially on long-range flights.